Collect. Czech. Chem. Commun. 1997, 62, 1159-1168

Humic Substances - Excited States, Quenching by Metal Ions, and Photosensitized Degradation of Chlorophenols

Kamil Langa, Dana M. Wagnerováa, Šárka Klementováb and Pavel Kubátc

a Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic, 160 00 Prague 6, Czech Republic
b Faculty of Biological Sciences, University of South Bohemia, 370 05 České Budějovice, Czech Republic
c J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, 182 23 Prague 8, Czech Republic


Alteration of photochemical properties of humic substances (HS) by the addition of metals abundant in natural waters has been investigated. Excited HS states have been characterized by fluorescence spectra and by laser kinetic spectroscopy. The effect of Cu2+, Fe2+, and Mn2+ has been explained in terms of static quenching of the HS excited states. In agreement with this, the metal ions were found to inhibit HS sensitized photooxidative degradation of chlorophenols.

Keywords: Humic substances; Quenching; Excited states; Photooxidative degradation; Chlorophenols.